High-frequency electric discharge device



' Oct. 14, 1947. NELSON 2,428,888

' HIGH-FREQUENCY ELECTRHIC DISCHARGE DEVICE Filed April 15, 1946 A y l 20 mil-$55 Inventor:

- His Attorney.

Richard B. Nelson,

Patented Oct. 14, 1947 Riherd B- 'on. Schenectady, Y. assigns? to General Electric Company,- a corporation or New York Application April 15 1946, Serial No. 662,134

My invention relates to high frequency electric discharge devices and more particularly to im- McArthur et al. application, and while not limited thereto is particularly well adaptedfor use in connection with fiat or radial resonators. The present invention provides numerous structural and manufacturing advantages resulting in a tube construction which is readily manufactured by production methods and which may be produced at a reasonable cost.

It is an object of my invention to provide a new and improved electric discharge device.

It is another object of my invention to provide anew and improved electric discharge de- Vice of the magnetron type which is capable of operating at high frequencies and which at the same time is relatively rugged and simple to manufacture. I

My invention will be better understood by reference to the following description, taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims. In the drawing, Fig. 1 is an elevational View of a magnetron embodyin my invention supported in operative relationship with respect to a flat resonator; Fig. 2 is a plan view taken along the line 2--2 of Fig. 1; Fig. 3 is an enlarged elevational view in section of the device shown in Fig. 1, and Fig. 4 is a section taken along the line 4--4 of Fig. 3,

Referring now to the drawing and particularly Fig. 3 thereof, I have shown my invention in an electric discharge device of the magnetron type in which a generally cylindrical envelope is provided by a cylinder I of insulating material, preferably glass or other vitreous material, to the opposite ends of which are sealed end structures 2 and 3.- Each of the end structures includes an axially extending cylindrical part 4 and-a marginal disk-like portion 5 sealed respectively to opposite ends of the cylinder I. The anode of the discharge device includes a plurality of elongated metallic members 6 to I3, inclusive, which are supported in mutually spaced and generally parallel relation in a circular array which is preferably concentric with the cylinder I. Alternate anode members, namely 6, 8, I

Claims. (Cl. 250=27.5)

and [2, are Supported from the upper end structure' by a ring-like member I l. The member I4 and associated anode members may to ad vantage be formed integrally and of a material such as molybdenum. As indicated on the drawing, the ring-like portion is received within the axially extending portion 4 of the end structime 2 and is weldedor otherwise bonded there: to. In a similar manner, the anode members 'I,' 9-, II and I3 are formed integrally with ring: like member I5 received within the axially extending portion 4 of the end structure 3. The dimensions of the anode members are such that the two sets supported from the opposite end structures are mutually insulated.

A source of electrons within the generally cylindrical space defined by the array of anode elements is provided by a helical-type cathode I6 having one end connected to a; suitable circular end shield I1 and the other end connected with a cylindrical block I8 supported adjacent the end of the anode members by an elongated sleeve IS'. The sleeve I9 provides an externally accessible terminal for one end of the cathode and is supported from the end structure 3 by a larger concentrically arranged sleeve 20 sealed at one end to the sleeve I9 by a body of glass 2|, and bonded at the other end to an annular ring 22 of steel or other suitable magnetic material. The ring 22 is bonded to the inner wall of the axially extending portion 4 or the end structure 3. The end plate I1 of the cathode structure is supported by a center post 23 which passes through. an opening 24 and is supported fromth'e sleeve I9by a cylindrical conductor 25 and by abody of glass 26. The end of the conductor 25' provides a terminal for the other end of the cathode. a

In a similar manner, the end structure 2 includes an annular ring 21 of steel or other magnetic material within which one end of a sleeve 21" is received. The sleeve is bonded to the ring 21 and is closed at its outer end by a body of glass 28' which encloses a getter 29 supported by a conductor 30. The body of glass may also be provided with an exhaust tubulation 3 I.

In Figs. 1 and 2 the magnetron device is shown in position in a flat resonator of rectangular cross section designated generally by the numeral 32 and including a pair of movable plungers 33 and 34 which may be adjusted in position to vary the effective dimensions of the cavity. As indicated on the drawing, the terminal portions 5 of the end structures of the discharge device are received in suitable recesses formed.

in the opposite side walls of the resonator. As indicated in Figs. 1 and 2, the resonator may be formed in two parts which are symmetrical about a longitudinal axis in order to facilitate the assembly of the device and the resonator. A suitable output connection for extracting high frequency energy from the resonator is provided by a concentric transmission line including an outer conductor 35 and an inner conductor 36 terminating in a loop portion 3! extending into the interior of the cavity. As illustrated, pole pieces 38 and 39 of an electromagnet not shown are arranged in cooperative relationship with the discharge device and particularly with the steel rings or pole pieces 22 and 21 to provide an axial magnetic field in the region between the cathode and the anode members.

Although the operation of the magnetron device embodying my invention is well understood, it may be briefly described as follows: With a suitable direct current voltage applied between the cathode and anode members and with a suitable axial magnetic field in the region between the anode members and the cathode, the electrons emitted by the cathode move in curvilinear paths to excite the resonant circuits provided by the anode members and the resonator to produce high frequency oscillations and the resultant electromagnetic field within the resonator from which energy may be extracted by the output transmission line, It is understood that the capacitive reactance of the resonant circuits is provided, to a large extent, by the closely spaced surfaces of adjacent anode segments and the inductive reactance, to a large extent, by the loops provided by the walls of the resonator and the short circuiting plungers. It will be readily understood that the position of the plungers determines the operating frequency of the system.

While I have shown and described a particular embodiment of my invention, it will be obvious to those skilled in the art that changes and modiflcations may be made without departing from my invention in its broader aspects, and I, therefore, aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

a ring supported within the flange portion of each of said members and supporting respectively alternate ones of said anode elements, a cathode supported from one of said members in insulated relation with respect thereto, and a pair of pole pieces positioned respectively within said flange portions and completing the envelope of said device.

2. An electric discharge device comprisin a hollow cylindrical insulator, a pair of closure members each including an apertured disk-like portion and an upstanding flange portion surrounding the aperture, said members having the disk portions sealed to opposite ends of said insulator and said flange portions extending outwardly, a plurality of elongated anode elements mounted in a cirular array with the individual elements extending in parallel and mutually spaced relation, alternate ones of said anode elements being supported respectively from the members sealed to opposite ends of said insulator, and a cathode supported from one of said flanges in insulated relation and with respect thereto.

3. An electric discharge device comprising a hollow cylindrical insulator, a pair of closure members each including an apertured disk-like portion and an upstanding flange portion surrounding the aperture, said members having the disk portions sealed to opposite ends of said cylindrical member, a plurality of elongated anode elements mounted in a circular array with the individual elements extending in parallel and mutually spaced relation, alternate ones of said anode elements being supported respectively from the members sealed to the opposite ends of said insulator, an annular pole piece positioned within one of said flange portions, a tubular member joined to said pole piece, a cathode supported from said tubular'member and positioned within said array of anode elements, and a pole piece positioned in the flange of the other of said members.

4. An electric discharge device comprising a hollow cylindrical insulator, a closure member having a marginal portion sealed to one end of said insulator and a flange defining a centrally located opening, a second closure member sealed to the opposite end of said insulator, a plurality of elongated anode elements mounted in a circular array with the individual elements extending in parallel mutually spaced relation, alternate ones of said anode elements being joined respectively to the closure members sealed to opposite ends of said insulator, an annular pole piece supported within said flange, and a cathode supported from said pole piece.

5. An electric discharge device comprising a hollow member of insulating-material having a substantially cylindrical cross section, a pair of closure members each having a disk-like portion sealed respectively to opposite ends of said members, at least one of said members having, a centrally located aperture defined by a flange extending substantially perpendicular to the disklike portion, a plurality of elongated anode elements mounted in a circular array with the individual elements extending in parallel and mutually spaced relation, a ring supported within the flange portion of said one member and supporting alternate ones of said anode elements, means supporting the remaining anode elements from the other of said closure members, and a cathode supported from one of said closure members and in insulated relation with respect thereto for supplying electrons to the inner electrode space between said cathode and said anode elements.

RICHARD B. NELSON. 

